Problem: Simplify the following expression: $k = \dfrac{2}{7x + 4} \div \dfrac{4}{4x}$
Solution: Dividing by an expression is the same as multiplying by its inverse. $k = \dfrac{2}{7x + 4} \times \dfrac{4x}{4}$ When multiplying fractions, we multiply the numerators and the denominators. $k = \dfrac{ 2 \times 4x } { (7x + 4) \times 4}$ $k = \dfrac{8x}{28x + 16}$ Simplify: $k = \dfrac{2x}{7x + 4}$